To improve light-emitting efficiency of the GaN-based chip, the substrate transfer technology has been developed in recent years. The transfer processes may include: depositing a GaN-based thin film over the sapphire substrate via MOCVD, bonding the GaN-based thin film to the semiconductor or metal base using wafer bonding technology or electroplating technique, and removing the sapphire substrate using laser lift-off method; or depositing a GaN-based thin film over the SiC or Si substrate, bonding the GaN-based thin film to the semiconductor or metal base using wafer bonding technology or electroplating technique, and removing the SiC or Si substrate using chemical etching method. In this way, the thin-film GaN chip can achieve a higher light-emitting efficiency by adding a reflecting layer between the epitaxial thin film and the base and obtaining a rough light-emitting surface using photochemical etching method over the N-polar surface GaN easily. At the same time, the GaN-based thin-film chip transferred to the heat dissipation base has relatively large advantages in large-current applications due to good thermal conductivity of the transferred base. Further improvements on existing luminous efficiency level are needed for popularizing semiconductor lighting in a true sense.